The mechanisms underlying transport across cell membranes have concerned physiologists for over a hundred years, and during most of that time it has been studied by cell-, electro-, and neuro-physiologists. In the last decade or so, however, there has been a burgeoning interest in cell membranes from a variety of other disciplines which have had an enormous impact not only in elucidating long-studied problems, but also in defining new areas of inquiry. This Gordon Conference will bring together outstanding investigators from several different disciplines who will address some of the major questions in membrane research today. From the intensive discussions among the conferees, the participants will gain a greater awareness of the breadth of existing problems and techniques in the field and hopefully will incorporate some of their new-found insights into their own thinking and research. The central role of proteins in membrane function is widely recognized, and two sessions will be devoted to this important area. One of them will focus on the structure of protein channels and transporters in membranes; the other will deal with the question of how proteins get inserted into and through membranes. Vesicle fusion with the plasma membrane is a ubiquitous phenomenon, occurring in such diverse processes as transmitter release at synapses, exocrine and endocrine secretion, and raising of the fertilization membrane after union of sperm and egg. It also is a means of inserting transport systems into the plasma membrane following hormonal stimulation. One session will deal with fusion, and talks in two other sessions will also treat this subject. Signalling and "learning" as they occur at the membrane level are beginning to be understood in terms of membrane proteins and their modification. Two sessions will address this topic. One will deal with modulation of ionic channels in synaptic plasticity, and one will be concerned with bacterial chemotaxis. Studies with lipid bilayers of late have been particularly revealing of biological transport phenomena. Two sessions will deal with planar bilayer membranes and phospholipid vesicles: one with reconstitution of biological channels in these systems and one with mechanisms of proton and ion transport through modified bilayers.